Method of producing color filter using a micellar disruption method

ABSTRACT

A process for producing color filters which enable a transparent electrode for forming a coloring matter film to be used as a transparent electrode for driving liquid crystals, and a resist for a light-shielding film used in this process for forming an insulating black matrix, is disclosed. The above production method comprises forming a black matrix over electrodes other than those corresponding to the individual separated colors and, at the same time, insulating layers as electrode contact window belts by utilizing the black matrix material; forming the electrode contact window belts by forming an electrically conductive layer over the black matrix so that they connect within each electrode contact window belt unit, but do not connect with those in different electrode contact window belt units; and forming a coloring matter layer by a micellar disruption method.

TECHNICAL FIELD

The present invention relates to a method of producing a color filterhaving a coloring matter layer prepared by a micellar disruption method,and relates to a resist for a light-shielding film used in this methodfor forming a black matrix.

BACKGROUND ART

Heretofore, several methods of producing a color filter used for adisplay for a liquid crystal TV, a personal computer and the like, havebeen known. Such known methods include:

(1) a dyeing method which comprises dyeing a gelatin layer formed on asubstrate, forming a photo-resist layer and curing the resist with aultraviolet ray;

(2) a dispersion method which comprises dispersing a dye in a resistmaterial, and then curing the resist material with the ultraviolet ray;

(3) a printing method which comprises directly printing a pattern for acoloring matter film and the like on a substrate; and

(4) an electrolytic method which comprises forming a dispersion of a dyein a suitable solvent, and subjecting the dispersion toelectrodepositing treatment utilizing an electrode formed on thesubstrate.

However, the above dyeing method (1) has a disadvantage in that theresultant filter has poor light resistance. The above dispersion method(2) shows a poor productivity due to a complexity of the steps. Further,the above printing method (3) is unsuperior in accuracy and lightresistance. On the contrary, the above electrodeposition method (4) isadvantageous since the resultant filter has good light resistance andhigh heat resistance. However, according to the method (4), theresultant filter needs a transparent electrode for forming a coloringmatter layer, and needs, on its surface, an electrode for driving aliquid crystal as is the same case with the above methods (1) to (3).

On the other hand, as a process for producing a color filter which iscapable of forming a conductive coloring matter layer, Japanese PatentApplication Laid-Open Gazette No. 63-243298 discloses a micellardisruption method which comprises forming a transparent electrode in adesired shape on an insulating substrate, and forming a poroushydrophobic coloring matter film on the electrode by a micellardisruption method.

Recently, a light-shielding film is indispensable to make a displaydevice such as a color filter, a liquid crystal display material, anelectron display material, and a color display. These display deviceshave widely been used in several fields such as a lap-top personalcomputer, a note type personal computer, an audio equipment, an insidepanel for an automotive, a clock, a calculator, a video cassette deck, afacsimile, a communication equipment, a game machine and a measurementequipment.

For example, in the fields of a color filter, a light-shielding film isused as a black matrix to be formed between each of picture elementssuch as red (R), green (G) and blue (B). Such black matrix is used toavoid lowering contrast and color purity due to leaked light.

Heretofore, in the case of forming each picture element (coloring matterlayer) such as a color filter by a printing method, a dispersion methodor a dyeing method, there have been used a carbon type photo-resistmaterial and a chromium film in many cases.

However, the use of the carbon type photo-resist material or thechromium film cannot give an electrode for driving a liquid crystal andan electrode for forming a coloring matter film at the same time due totheir conductivity. More specifically, when a black matrix is firstformed, using the photo-resist material or the chromium film, on an ITOelectrode on which a pattern was formed for forming a coloring matterlayer, the ITO electrode will be electrically connected with a right andleft side electrodes. Thus, a coloring matter layer cannot be formed bya micellar disruption method and the like. On the contrary, when a blackmatrix is formed after a coloring matter layer is formed, there will bea problem that a liquid crystal cannot work due to electrical connectionbetween the ITO electrode and a right and left side electrodes duringliquid crystal operation. Accordingly, the use of the carbon typephoto-resist material results in a problem that a micellar disruptionmethod and an electro-deposition method cannot be used to form acoloring matter layer.

Accordingly, it has been desired to develop a resist for alight-shielding film which has an insulating property. Thus, organic dyetype photo-resist materials have been developed. The light-shieldingfilm made from the conventional insulating organic dye type photo-resistmaterial is formed by a photo-lithography method by mixing three kindsof photo-resists including dyes for red (R), green (G) and blue (B), ortwo kinds of photo-resists including dyes of red (R) and blue (B). Thus,the resultant light-shielding film has poor light-shielding ratio. Toobtain a sufficient light-shielding ratio, it is necessary to make filmthicker.

The present invention was made in view of the above situations, and hasits object to provide a process for producing a color filter in which atransparent electrode can be used both for forming a coloring matterlayer during the color filter preparation and for driving a liquidcrystal after the color filter has been produced. Further, rt is anotherobject of the present invention to provide a resist for alight-shielding film capable of forming a light-shielding film having angood insulating property and a high light-shielding ratio.

DISCLOSURE OF INVENTION

According to the present invention, there is provided a process forproducing a color filter prepared by laminating an insulating substrate,a transparent electrode, a black matrix and a coloring matter layer inthis order, and having, near one side of the color filter surface, anelectrode contact zone composed of electrode contact window belts foreach of the transparent electrodes corresponding to individual separatedcolors,

said process comprising forming a black matrix over electrodes otherthan those corresponding to the individual separated colors and, at thesame time, insulating layers as electrode contact window belts byutilizing the black matrix material; forming the electrode contactwindow belts by forming an electrically conductive layer over the blackmatrix so that the electrode contacts for one color connect with eachother. within each electrode contact window belt unit, but do notconnect with those for the other colors in different electrode contactwindow belt units; and forming a coloring matter layer by a micellardisruption method.

In the process for producing a color filter according to the presentinvention, an insulating black matrix and an electrode contact windowbelt for taking out an electrode in a part of a color filter are formedat the same time, and then a conductive coloring matter layer islaminated on a transparent electrode by a micellar disruption method.Thus, it is easy to produce a color filter in which an electrode forforming a coloring matter layer can be used also for driving a liquidcrystal.

Further, the resists for light-shielding film of this invention includea resist for a light-shielding film comprising at least one of aninsulating organic dye dispersed resist and an insulating transparentresist, and a conductive high light-shielding resist (first resist); aresist for light-shielding film comprising two or more kinds ofinsulating organic dye dispersed resists (second resist); and a resistfor a light-shielding film composed of an insulating transparent resistcontaining a black organic dye dispersed therein (third resist). Theresultant light-shielding film preferably has a surface resistance ofnot less than 10⁷ Ω/cm².

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view of one example of the colorfilter according to the present invention;

FIG. 2 is a plan view showing a mask for forming a transparentelectrode;

FIG. 3 is a plan view showing a mask for forming a black matrix and anelectrode contact zone;

FIGS. 4 and 5 are cross-sectional views of an electrode contact zone;and

FIG. 6 is a flow chart showing one example of production steps of alight-shielding film by way of a photo-lithography method.

In these figures, 1 denotes a glass substrate, 2 denotes a transparentelectrode, 3 denotes a black stripe, 4 denotes a coloring matter, 5denotes a coating layer and 6 denotes an orientation layer.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail below.

In the process for producing a color filter according to the presentinvention, a black matrix is first formed over electrodes other thanthose corresponding to the individual separated colors. The material forthe black matrix forms insulating layers as electrode contact windowbelts. Then, electrically conductive layers are formed on the matrix sothat the electrodes connect within each electrode contact window beltunit, but do not connect with those in different electrode contactwindow belt units. Then the coloring matter layer is formed by themicellar disruption method.

One of the embodiments will be described with reference to FIG. 1. Toproduce a color filter 10, firstly, a surface of an insulating glasssubstrate 1 (for example, plates of blue plate glass, non-alkali glassand quartz glass) is sufficiently washed with an alkali aqueous solutionor pure water.

Then, a transparent electrode material layer is formed on one side ofthe glass substrate 1 by way of a vapor deposition method, a sputteringmethod, a bio-sol method, a ultra small particle casting method or thelike. The electrode material layer is subjected to surface oxidationtreatment or baking treatment to adjust resistance. Then, a resistmaterial (such as UV curable resin) is coated on the electrode materiallayer by a spin coating method, a dipping method or a casting method.The coated substrate is subjected to exposure treatment (for example, UVexposure) using a suitable mask, and the unexposed portions of theresist material are washed and removed after development. The exposedand remaining resist material is cured, and the exposed electrodematerial is subjected to etching treatment with an etching liquid and isremoved. Then, the cured and remaining resist is also removed. Thetreated substrate is washed and transparent electrodes 2 (2B, 2G, 2R)corresponding to each of the primary colors are formed. Then, a blackmatrix or stripe 3 is formed on the glass substrate 1 carrying thetransparent electrodes 2 by a photo-lithography method as described indetail below. For example, the resist for a light-shielding film of thepresent invention such as a resist material consisting of a UV curableresin and a black dye is coated on the substrate with a spin coater or aroll coater. The resist is subjected to exposure treatment with asuitable mask for a black stripe, followed by usual procedures includingwashing, development, washing and baking. The mask 20, as shown in FIG.2, is for a positive resist. Since the UV curable resin is a negativeresist, a proper mask which can be used for the process mentioned inthis paragraph should be a mask whose light shielding and passingsections are reversed from those of the mask 20 shown in FIG. 2.

If a mask for a transparent electrode and a mask for a black matrix areappropriately selected, electrode contact window belts can be formed ina part of a color filter simultaneously with formation of a blackmatrix. For example, when transparent electrodes are formed on a glasssubstrate using the mask 20, ten repeating units of electrode lines,each consisting of three electrode lines (shortest line 2B, medium sizeline 2G, longest line 2R), are formed so that electrode lines 2B, 2G and2R respectively correspond to these lines 21B, 21G and 21R for the threeprimary colors of a light, blue (B), green (G) and red (R).

A black matrix is formed using, for example, a mask 30 as shown in FIG.3. The mask 30 has a pattern 32 for forming electrode contact zones aswell as a pattern 31 for forming a black matrix. A pattern 32 iscomposed of patterns for forming three electrode contact window belts,which consist of a pattern 32B for forming an electrode contact windowbelt for an electrode line (B); a pattern 32G for forming an electrodecontact window belt for an electrode line (G); and a pattern 32R forforming an electrode contact window belt for an electrode line (R). Itis preferable to use the resist for a light-shielding film according tothe present invention to form a black matrix and an insulating layer atthe same time.

Sections of electrode contact zones of a color filter prepared by usingthe mask 20 and the mask 30 are shown in FIGS. 4 and 5. FIG. 4 is across-sectional view, taken along line IV-IV in the mask 30, of a colorfilter; and FIG. 5 is a cross-sectional view, taken along line V-V inthe mask 30, of a color filter. As shown in FIGS. 4 and 5, the electrodelines 2G and 2R are coated with an insulating layer 41, but theelectrode lines 2B are electrically connected with each other through aconductive layer 42.

The resist for a light-shielding film according to the present inventionsuitably used for forming the above black matrix, will be described indetail below.

The first resist of the present invention comprises at least one of aninsulating organic dye dispersed resist and an insulating transparentresist, and a conductive high light-shielding resist.

The insulating organic dye dispersed resists include, for example, aresist in which an insulating organic dye is dispersed, such as an acryltype resist, an epoxy type resist and a polyimide type resist.

The insulating organic dyes include, for example, perylene type dyes,anthraquinone type dyes, dianthraquinone dyes, azo type dyes, diazo typedyes, quinacridone type dyes, and anthracene type dyes. Morespecifically, examples of the insulating organic dyes are a perylenedye, quinacridone, Naphthol AS, a shikonin dye, dianthraquinone, SudanI, II, III or R/ bisazo, and benzopyran.

The blue dyes include, for example, phthalocyanine type dyes, copperphthalocyanine type dyes, indathrone type dyes, indophenol type dyes andcyanine type dyes. More specifically, examples of the blue dyes aremetal complexes of phthalocyanine such as chlorinated copperphthalocyanine, chlorinated aluminum phthalocyanine, vanadic acidphthalocyanine, magnesium phthalocyanine, zinc phthalocyanine, ironphthalocyanine, cobalt phthalocyanine; phthalocyanine; merocyanine; andindophenol blue.

Further, as commercially available insulating organic dye dispersedresists, organic dye dispersed resist containing a yellow (Y) organicdye, a violet (V) organic dye and the like (Color Mosaic CR, CG, CB, CY,CV, etc.; Manufactured by Fuji Hunt Technology, Co.) are available inaddition to resists containing a red (R), green (G) or blue (B) organicdye.

The insulating transparent resists include any transparent resistshaving an insulating property, for example, UV curable resists. Morespecifically, the insulating resists include ALONIX (acryl type resin;Manufactured by Toa Gosei, Co.); and TORAY PHOTONIS (Manufactured byToray, Co.)

The conductive resists having a high light-shielding property include,for example, a conductive particle dispersed resists which are thoseresists containing conductive particles dispersed in a acryl typeresist, an epoxy type resist and a polyimide type resist. In this case,examples of the conductive particles are high light-shielding materialssuch as carbon, chromium oxide and small metal particles.

The first resist containing the above resists (insulating organic dyedispersed resist, insulating transparent resist, conductive highlight-shielding resist), are usually prepared by mixing the aboveresists. Further, for instance, the first resist can be prepared bydispersing insulating organic dye and conductive high light shieldingparticles in one of the resist materials. In any preparation methods, itis preferable to mix each dye and conductive particles with a resist sothat they are uniformly dispersed in the resist material.

The mixing ratio can be selected appropriately. However, in the case ofusing a micellar disruption method, it is preferable to select themixing ratio so that resultant light-shielding film has a surfaceresistance of 10⁷ Ω/cm² or more. At the time of mixing, a solvent can beadded. A mixing equipment which can avoid heat generation, is preferablyused to prevent resists from being aggregated.

The second resist comprises at least two kinds of insulating organic dyedispersed resist. The above description for the first resist can beapplied to the insulating organic dye dispersed resists for the secondresists.

The preparation methods include, for example, a method comprising mixingtwo kinds of photo-resist materials, each having one color dye differentfrom each other; and a method comprising mixing two dyes (two colors)with one of resist materials and then dispersing the dyes in the resistmaterial. In any methods, it is preferable to mix the dyes with theresist material so that each dye can be uniformly dispersed in theresist material.

The above description about the mixing ratio, the surface resistance andthe like can be also applied to the second resist.

The third resist is an insulating transparent resist containing a blackorganic dye dispersed therein. The above description about theinsulating transparent resins can also be applied to the third resist.

The black organic dyes include, for example, Perillene Black, AnilineBlack, and Cyanine Black. Two or more kinds of the black organic dyescan be dispersed in the insulating transparent resist. It is preferablethat the black organic dye be uniformly dispersed in the resist.

In addition, the first, second and third resists can be positive type ornegative type UV curable resists, and can be EB resists, X-ray resistsand the like.

In the practice of the production of the color filter according to thepresent invention, it is preferable to use the above first, second orthird resist to form a black matrix with the use of a photo-lithographymethod.

FIG. 6 is a flow chart showing steps of production of a light-shieldingfilm by way of a photo-lithography method.

(1) Firstly, any one of the above first, second and third resists iscoated on a substrate made of glass and the like. The coating methodsinclude coating using a spin coater or a roll coater; and spray coatingusing a compressor. The rotation speed for a spin coater or a rollcoater can be selected appropriately depending upon viscosity of aresist, desired film thickness, and the like, and may range, forexample, from 500 to 3,000 rpm.

(2) The substrate coated with the resist for a light-shielding film isthen subjected to exposure treatment. The exposure is conducted with anexposing equipment using a photo-mask having a desired pattern. By theuse of the photo-mask, a portion of a resist corresponding to thepattern of the photo-mask is exposed to light. The exposing equipmentand the exposing conditions can be selected appropriately, and cannot bespecifically limited. The amount of exposure may range, for example,from 20 to 200 mI/cm².

Further, a source of light is determined depending uponphoto-sensitivity of a resist for a light-shielding film. For example, a2KW high voltage mercury lamp can be used.

(3) After exposure, pre-baking is carried out. The pre-baking is carriedout for the purpose of increasing adhesiveness between a substrate and aresist for a light-shielding film before development, resulting inprevention of deficiencies during development.

The pre-baking is conducted by heating with an oven, a hot plate and thelike. The pre-baking temperature and heating time can be selectedappropriately depending upon the resist used. The pre-baking temperatureand time may range, for example, from 85° to 100° C. and from 5 to 10minutes, respectively.

(4) After pre-baking development is carried out. The development iscarried out for the purpose of removing an unexposed portion of a resist(in the case of negative resist) or an exposed portion of a resist (inthe case of positive resist). The development forms a desired pattern onthe substrate. A developing liquid can be preferably selected from thosecapable of dissolving and removing a resist, depending upon the contentof the resist used. An appropriate development liquid is commerciallyavailable for each commercial resist material. Thus, such commercialproducts can be used, however alkali aqueous solution is mainly used.

The concentration of the developing liquid and development time can beappropriately selected depending upon the resist to be used and thedeveloping liquid used. The development time may range, for example,from 20 to 30 seconds.

(5) After development, the obtained substrate is rinsed by immersing itin a pure water. The rinsing is carried out to remove the developingliquid.

(6) After rinsing, post-baking is carried out. The post-baking iscarried out, for example, to improve adhesiveness between the resist fora light-shielding film and the substrate. The post-baking is conductedas is the same case with the pre-baking, by heating with an oven, a hotplate and the like. The post-baking temperature and time may range, forexample, from 200° to 220° C. and from 5 to 10 minutes, respectively.

In the process of the present invention, after the above-mentioned blackmatrix is formed, a coloring matter layer consisting of conductiveporous and hydrophobic coloring matter thin film, is formed on atransparent electrode by way of a micelle-electrolytic method. Thephrase "conductive porous film" means that the film or layer is porousso as to have enough conductance. In other words, the film or layer hasconductance to extent that a transparent electrode located under thefilm or layer can be used for driving a liquid crystal and the like.Thus, the material itself of the film or layer needs not to beconductive.

To form the above coloring matter thin film by a micellar disruptionmethod, the following procedures can be used.

A micelle forming agent comprising ferrocene derivatives and a coloringmatter material (hydrophobic coloring matter) are added to an aqueoussolvent having a controlled conductance prepared by adding, asnecessary, a support electrolyte to water. The mixture is well stirredto obtain a micelle containing the coloring matter material therein.When the micelle solution is subjected to electrolytic treatment, themicelle moves to an anode. The ferrocene derivative contained in themicelle loses an electron, e⁻ (Fe²⁺ of the ferrocene is oxidized toFe³⁺) on the anode (transparent electrode), and at the same time themicelle is broken. When the micelle is broken, a coloring mattermaterial is precipitated on the anode to form a thin film.

On the other hand, the oxidized ferrocene derivative moves to a cathodeand receives an electron, e⁻ to reform a micelle. While the micelleformation and breakage are repeated, coloring matter particles areprecipitated on the transparent electrode to form a thin film. Thedesired coloring matter thin film is formed in this manner. The thusobtained coloring matter thin film has, in general, a thickness of 0.1to 10.0 μm, preferably 0.1 to 2.0 μm. Due to the porous structure of thethin film, the thin film has high conductance. If the film thickness isless than 0.1 μm, the hue of the coloring matter layer cannotsufficiently be exhibited. If the thickness is more than 10.0 μm, thefilm will have low conductance. Thus, the thin film having the abovethickness range is preferable.

The micelle forming agents which can be used in a micellar disruptionmethod are those comprising ferrocene derivatives. The ferrocenederivatives include several types, and may be those represented by thegeneral formula [I]: ##STR1## wherein R¹ and R² are independently a C₁₋₆alkyl group, C₁₋₆ alkoxy group, amino group, dimethylamino group,hydroxyl group, acetylamino group, carboxyl group, methoxycarbonylgroup, acetoxy group, aldehyde group or halogen; R³ is hydrogen or alinear or branched C₄₋₁₈ alkyl group or alkenyl group; R⁴ and R⁵ areindependently hydrogen or a methyl group; Y is oxygen, an oxycarbonylgroup or acyloxy group; a is an integer of 0 to 4; b is an integer of 0to 4; m is an integer of 1 to 18; and n is a real number of 2.0 to 70.0.

These compounds are described in, for example, PCT InternationalPublication for WO 88/07538 and WO 89/01939, and a patent specificationof JP Patent Appln. No. 63-233797.

In R¹ and R², the C₁₋₆ alkyl groups include a methyl group (CH₃) andethyl group (C₂ H₅); the alkoxy groups include a methoxy group (OCH₃)and ethoxy group (OC₂ H₅); halogen includes chlorine, bromine, fluorineand iodine. R¹ and R² may be the same as or different from each other.Further, when R¹ and R² independently exist in a plurality offive-membered rings of the ferrocene, a plurality of substituted groupsmay be the same as or different from each other. In addition, ##STR2##in the general formula [I] include, for example, ##STR3##

Further, n means a number of a repeating unit which is the aboveoxyalkylene group. The number "n" includes a real number of the repeatedoxyalkylene group (thus means average number) as well as an integer of2.0 to 70.0. The ferrocene derivatives which can be used in the micellardisruption method include several ones in addition to those representedby the general formula [I]. Such ferrocene derivatives include ammoniumtype, pyridine type (PCT International Publication WO 88/07538, etc.)and those described in patent specifications of JP Patent Appln. Nos.53-233797; 63-233798; 63-248660; 63-248601; Hei 1-45370; Hei 1-54956;Hei 1-70680; Hei 1-10681; Hei 1-76498; and Hei 1-76499.

These ferrocene derivatives are capable of effectively dissolving ordispersing hydrophobic substances in an aqueous medium.

In the micellar disruption method used in the present invention, amicelle forming agent comprising a ferrocene derivative, a supportingsalt, and a hydrophobic organic substance are placed in an aqueousmedium and thoroughly dispersed by the use of supersonic waves, ahomogenizer, or a stirrer to from a micelle. Thereafter, if necessary,an excessive coloring matter material is removed. The micelle solutionthus obtained is subjected to electrolytic treatment using thetransparent electrode while allowing to stand or somewhat stirring.During the electrolytic treatment, the coloring matter material may besupplementarily added to the micelle solution, or there may be provideda recycle circuit in which the micelle solution in the vicinity of theanode is withdrawn out of the system. The coloring matter material isadded to the withdrawn micelle solution and thoroughly stirred, and thenthe resulting solution is returned to the vicinity of the anode. In thiscase, the concentration of micelle forming agent may be at least thecritical micelle concentration, more specifically about 0.1 mM or more.The concentration of the coloring matter material may be saturatedconcentration or higher.

Electrolytic conditions are determined appropriately depending onvarious circumstances. Usually, the liquid temperature is 0° to 70° C.,preferably 5° to 40° C. The voltage is not less than oxidation-reductionpotential of the ferrocene derivative as micelle forming agent, but notgreater than hydrogen generation potential, and more specifically is0.03 to 1.00V, preferably 0.15 to 0.7 V. The current density is not morethan 10 mA/cm², preferably 50 to 300 A/cm².

On performing this electrolytic treatment, the reaction proceeds inaccordance with the principle of the micellar disruption method.Explaining in connection with the behavior of Fe ion in the ferrocenederivative, Fe²⁺ is converted into Fe³⁺ on an anode, leading to thebreakdown of the micelle. Particles of a coloring matter material aredeposited on the anode. On the other hand, on a cathode, Fe³⁺ oxidizedon the anode is reduced to Fe²⁺, recovering the original micelle and,therefore, a film forming operation can be carried out repeatedly usingthe same solution.

Electrolytic treatment as described above forms a thin film composed ofthe desired coloring matter material on the anode.

The supporting salt (supporting electrolyte) to be used in the processof the present invention is added, if necessary, in order to control theelectrical conductance of the aqueous medium. The amount of thesupporting salt added is such that the precipitation of coloring mattermaterial dissolved or dispersed is not prevented, and is usually about 0to 300 times, preferably about 50 to 200 times that of the above micelleforming agents. It is possible to perform the electrolytic treatmentwithout using the supporting salt. In this case, highly pure thin filmcontaining no supporting salt is obtained. The type of the supportingsalt is not critical as long as capable to control the electricconductance of the aqueous medium without inhibiting the formation ofthe micelle and the deposition of the above coloring matter material.

More specifically, the supporting salts which have widely been usedinclude, for example, sulfuric acid salts (salts of lithium, potassium,sodium, rubidium, aluminum and the like}; acetic acid salts (salts oflithium, potassium, sodium, rubidium, beryllium, magnesium, calcium,strontium, barium, aluminum and the like); salts of halogenatedcompounds (salts of lithium, potassium, sodium, rubidium, magnesium,calcium, aluminum and the like); and water-soluble oxide salts (salts oflithium, potassium, sodium, rubidium, magnesium, calcium, aluminum andthe like).

The electrode to be used in the process of the present invention issufficient to be a metal more noble than the oxidation potential(against+0.15V to 0.30V saturated calomel electrode) of ferrocene, or anelectrically conductive substance. More specifically, ITO (mixed oxideof indium oxide and tin oxide), tin oxide, electrically conductiveorganic polymers, and the like can be used.

In the production process of the present invention, the coloring mattermaterials for forming a coloring matter film include several onesincluding those exhibiting the three primary colors for light, such as ahydrophobic coloring matter material for red, green or blue. The redcoloring matter materials include, for example, perylene type dyes, lakedyes, azo type dyes, quinacridone type dyes, anthraquinone type dyes andanthracene type dyes, and more specifically include a perylene dye, lakedyes (Ca, Ba, Sr, Mn), quinacridone, Naphthol AS, a shikonin dye,dianthraquinone, Sudan I, II, III or R, bisazo, and benzopyran, cadmiumsulfide type dyes, Fe (III) oxide type dyes. Of these, the perylene dyeand the lake dye are preferred.

The green coloring matter materials include, for example, halogenatedmulti-substituted phthalocyanine type dyes, halogenatedmulti-substituted copper phthalocyanine type dyes and triphenylmethanetype basic dyes, and more specifically include chlorinatedmulti-substituted phthalocyanine, its copper complex and abarium-triphenylmethane dye. Further, the blue coloring matter materialsinclude, for example, copper phthalocyanine type dyes, indathrone typedyes, indophenol type dyes and cyanine type dyes, and more specificallyinclude metal complexes of phthalocyanine such as chlorinated copperphthalocyanine, chlorinated aluminum phthalocyanine, vanadic acidphthalocyanine, magnesium phthalocyanine, zinc phthalocyanine, ironphthalocyanine, cobalt phthalocyanine; phthalocyanine; merocyanine; andindophenol blue.

In the present invention, in the case of preparing hydrophobic coloringmatter thin film for the three primary colors, any one of red, green andblue hydrophobic coloring matters is first added to an aqueous medium,and the first desired color thin film is formed by the above-mentionedmicellar disruption method. Then, the micelle electrolytic treatment isrepeatedly carried out using different hydrophobic coloring matter toform coloring matter films for the three primary colors (red, green,blue) on each transparent electrode.

In addition, it is possible to get hydrophobic coloring matters for red,green and blue dispersed in an aqueous medium at the same time, andsubject the aqueous medium to the micelle electrolytic treatment toproduce the same color filter.

Further, if necessary, a top coating material may be coated with a spincoater or a roll coater on the coloring matter layer and a black matrixand dried at 80° to 150° C. for 5 to 60 minutes to form a conductivecoating layer. The top coating material include, for example, an acrylresin, polyether resin, polyester resin, polyolefin resin, phosphazeneresin, or polyphenylene sulfide resin. The coating layer allows asurface to be contacted with a liquid crystal to be flat. If the coatinglayer is prepared from a conductive material, voltage down due to thecoating layer can be prevented. Further, transparent conductiveparticles such as ITO particles can be added to these coating materials.

At the last, if necessary, an orientation layer as the most upper layermay be formed by coating, for example, a polyamic acid monomer, apolyimide resin oligomer or the like by a spin coater or a roll coater,polymerizing the coated material at 200 to 300° C. for 30 minutes to 2hours, washing with pure water or the like, and drying the polymerizedproduct (at 60° to 100° C. for 30 minutes to 2 hours or by UV radiationor the like). The liquid crystals can be oriented by the orientationlayer.

The present invention will be described with reference to the followingexamples, which are not intended to limit the scope of the invention.

EXAMPLE 1 Formation of Transparent ITO Electrode

A glass substrate (NA45; Manufactured by HOYA; size 320×300×0.5 mm) waswashed with 0.1N NaOH, and washed with pure water until the liquidresistance of the used water became 10⁷ Ω/cm². The washed substrate wasplaced in a vacuum sputtering equipment and then subjected to sputteringtreatment using ITO. The surface of the thus formed ITO layer wasoxidized in air at 100° C. to adjust the surface resistance to 100Ω/cm². And then, a resist material (FH-2130; Manufactured by Fuji HuntElectronics Technology, Co.) was coated over the ITO layer with a rollercoater, baked at 80° C. for 5 minutes, subjected to UV radiation (60seconds) with a 500W high pressure mercury lamp using a stripe mask asshown in FIG. 2. In addition, width of each line of the mask as shown inFIG. 2 was 90 μm, and distance between each line was 20 μm.

And then, the obtained product was washed with water, and the ITO coatedwith the resist material was immersed in a developing liquid (HPRD-410;Manufactured by Fuji Hunt Technology, Co.), and then developed for 5minutes. Further, the obtained product was washed with pure water andthen heated to 230° C. for 5 minutes. After sufficiently curing theresist material, the product was immersed in 1N.HCl/IM.FeCl₃ etchingliquid to subject the ITO to etching treatment for 20 minutes. Afteretching, the product was washed with pure water, and the cured resistwas removed with the use of a resist removing agent (Microstrip 2001;Manufactured by Fuji Hunt Technology, Co.). Then the product was furtherwashed.

Formation of Black Stripe

A resist film was formed on the ITO carried substrate as prepared above,by coating a color resist containing a UV curable polymer and a blackdye (Color Resist CK; Manufactured by Fuji Hunt Electronics Technology,Co.) by a spin coating at 3,000 rpm. The coated substrate was pre-bakedat 80° C. for 5 minutes, and further coated with polyvinyl alcohol asoxygen resist material by spin coating at 400 rpm. After that, theresist material was pre-baked at 80° C. for 5 minutes, and subjected toUV radiation with a 500W high pressure mercury lamp using a mask forblack stripe as shown in FIG. 3. In addition, the mask of FIG. 3 had apattern for a black stripe having an inner size of 90×310 μm, a linewidth of 20 μm, and a pattern for electrode contact windows having aninner size of 90 μm×5 mm. After washing with water, the resist wasdeveloped using a color resist developing liquid (CD; Manufactured byFuji Hunt Electronics Technology, Co.) The thus obtained product waswashed with pure water, and then post-baked at 230° C. for 10 minutes.In this manner, the black stripe and the electrode contact window foreach electrode line corresponding to each of the three primary colors,were formed at the same time. And then, three electrode contact windowbelts were formed by coating conductive silver paste in the shape ofbelts so that the electrode lines for the same color were electricallyconnected, but the electrode lines for different colors were notconnected.

Formation of coloring Matter Layer

From one to two grams of each of a red dye (Lithol Scarlet K3700;Manufactured by BASF), a green dye (Heliogen Green L9361; Manufacturedby BASF); and a blue dye (Heliogen Blue B7080; Manufactured by BASF) wasadded to and dispersed in a 2 mM aqueous solution of a compound (FPEG)represented by the following formula: ##STR4## Further, 0.1M of lithiumbromide (supporting salt) was added to and dispersed in the mixture witha ultrasonic homogenizer for 30 minutes, and the mixture was stirredwith a stirrer for 3 days to prepare coloring matter dispersedsolutions.

The substrate obtained as above was immersed in the red dye dispersedsolution (an electrode contact zone was not immersed), and then micelleelectrolytic treatment (0.5V, 25° C., 30 minutes) was carried out usingan electrode contact window belt for an electrode line for a redcoloring matter. A saturated calomel electrode as reference electrodeand an aluminum plate as cathode were used. After the electrolytictreatment, the substrate was washed with pure water, baked at 180° C.for 1 hour to obtain a red coloring matter layer 4R.

Following the same procedures, a green coloring matter layer 4G and ablue coloring matter layer 4B were formed.

The average film thickness of each coloring matter layer was 0.5 μm(red), 0.4 μm (green) and 0.6 μm (blue), respectively.

Formation of Coating Layer and Orientation Layer

The obtained substrate was coated with a top coating material (OPTOMARJHR; Manufacture by Nippon Synthetic Rubber) by spin coating at 3,000rpm, and baked at 80° C. The thus coated substrate was further coatedwith a N-methylpyrrolidone solution of polyamic acid by spin coating inthe same manner, and the coated polyamic acid was polymerized undervacuum atmosphere at 250° C. for 1 hour. After washing with pure water,the washed substrate was dried at 80° C. for 1 hour to obtain a colorfilter of the present invention having a conductive coating layer 5 (0.2μm) and an orientation layer 6 (0.1 μm).

Further, the color filter was subjected to sputtering treatment usingITO to form the ITO layer on the oriented layer 6. The resistancebetween this ITO and the ITO formed inside of the color filter wasmeasured by a tester, and the resistance was 10⁵ Ωcm². The insulatingresistance between the ITOs was 10¹³ Ω/cm². Thus, it was confirmed thatthe an electrically conductive color filter was formed.

EXAMPLE 2 Formation of Transparent ITO Electrode

A glass substrate (NA45; Manufactured by HOYA; size 300×300 mm) having asurface resistance of 20 Ω/cm² as an ITO film was coated with a 50%xylene solution of a UV curable resist material (IC-28/T3; Manufacturedby Fuji Hunt Electronics Technology) by spin coating at 1000 rpm. Afterspin coating, the coated substrate was pre-baked at 80° C. for 15minutes. And then, this resist/ITO substrate was placed in an exposingequipment.

A mask used had a stripe pattern having a. line width of 100 μm, a gapof 20 μm and a line length of 155 kN. A 2KW high voltage mercury lamp(exposure ability: 10 mW/cm².s) was used. The proximity gap was set as70 μm. After 60 second exposure, the resist was developed with adeveloping liquid. After development, the treated product was rinsedwith pure water, and post-baked at 180° C. And then, the product wassubjected to etching treatment using an etching liquid consisting of 1MFeCl₃, 1N HCl, 0.1N HNO₃, 0.1N Ce(NO₃)₄. The etching treatment took 40minutes. After etching, the product was washed with pure water, and theresist was removed by the use of 1N NaOH.

Following the above procedures, the ITO electrode in the shape of stripwas formed on the glass substrate.

Formation of Resist for Licht-Shieldinq Film and Black Stripe

There was used a resist for a light-shielding film (resist for forming ablack matrix) prepared by mixing a conductive high light-shieldingresist (CK; Manufactured by Fuji Hunt Electronics Technology) and aninsulating transparent resist (acryl type resist cellosolve acetate 10%solution; Manufactured by Toa Gosei) at a conductive resist/insulatingresist ratio, by weight, of 3:1.

While the ITO patterning substrate as prepared above was rotated at 10rpm, 30 cc of the above resist for a light-shielding film was sprayedthereon. Then, the substrate was subjected to spin coating at 2500 rpmto form an uniform film. The coated substrate was pre-baked at 80° C.for 15 minutes. The obtained product was subjected to exposure by anexposing machine having a 2kW high pressure mercury lamp and analignment function, using a photo-mask for forming a black matrixpattern, while positioning the product. After that, the resist wasdeveloped using a color resist developing liquid (CD; diluted 4 times;Manufactured by Fuji Hunt Electronics Technology, Co.) for 30 seconds.The thus obtained product was rinsed with pure water, and thenpost-baked at 200° C. for 100 minutes. In this manner, the black stripeand the electrode contact window for each electrode line correspondingto each of the three primary colors, were formed at the same time.

Formation of Coloring Matter Layer

A micelle solution was prepared by adding a micelle forming age of aferrocene derivative (Manufactured by Dohjin Chemical), LiBr(Manufactured by Wako Pure Chemical) and CROMOPHTHAL A2B (Manufacturedby Chiba-Geigy) to 4L of pure water to prepare 2 mM/1 solution, 0.1M/lsolution and 10 g/l solution. The obtained solutions were stirred with aultrasonic homogenizer for 30 minutes to obtain micelle solutions. Thesubstrate prepared as above was immersed in the micelle solution (anelectrode contact zone was not immersed). A red coloring matter layerfor a color filter was formed by connecting an electrode line for a redcoloring matter (stripe R) with a potentiostat, and carrying outconstant potential electrolytic treatment at 0.5V. After theelectrolytic treatment, the obtained product was washed with pure water,and pre-baked with an over at 180° C.

Following the same procedures, a green coloring matter layer and a bluecoloring matter layer were formed in this order, using a green dye(Heliogen Green L9361; Manufactured by BASF), and a blue dye (HeliogenBlue B7080; Manufactured by BASF), respectively.

The black stripe of the thus obtained color filter had a film thicknessof 1.7 μm, a light-shielding ratio of 92% and a surface resistance of10⁹ Ω/cm².

The color filter was produced in such a way that the formed RGB filterhad a thickness within 0.6 to 1.0 μm and had a relatively flat surface,and that the thin film was not formed on the electrodes other than thosefor passing electricity. In addition, it was found that the color filterhad a resistance of 10⁵ Ω/cm², and that the color filter was anelectrically conductive one.

EXAMPLE 3

The same procedures as used in Example 2 were repeated except that therewas used a resist for a light-shielding film prepared by mixing aconductive high light-shielding resist (CK; Manufactured by Fuji HuntElectronics Technology), an insulating organic dye (red) dispersedresist (CR; Manufactured by Fuji Hunt Electronics Technology), aninsulating organic dye (green) dispersed resist (CG; Manufactured byFuji Hunt Electronics Technology), and an insulating organic dye (blue)dispersed resist (CB; Manufactured by Fuji Hunt Electronics Technology)at a CK/CR/CG/CB resist ratio, by weight, of 3:1:1:1, and that therotation speed for spin coating was changed to 2000 rpm during blackmatrix formation, to produce a color filter.

As a result, the black matrix had a film thickness of 1.9 μm and alight-shielding ratio of 93% which was extremely high. The black matrixhad a surface resistance of 10¹⁰ Ω/cm². Thus, it was found that thecolor filter was produced without forming a thin film on the electrodesother than those for passing electricity. Also, it was found that thecolor filter was electrically conductive since the color filter had aresistance of 10⁵ Ω/cm².

EXAMPLE 4

The same procedures as used in Example 2 were repeated except that therewas used a resist for a light-shielding film prepared by mixing aconductive high light-shielding resist (CK; Manufactured by Fuji HuntElectronics Technology), and an insulating transparent resist (acryltype resist ARONIX cellosolve acetate 10% solution; Manufactured by ToaGosei) at a conductive resist/insulating resist ratio, by weight, of1:1, and that the rotation speed for spin coating was changed to 1000rpm during black matrix formation, to produce a color filter.

As a result, the black matrix had a film thickness of 2.3 μm and alight-shielding ratio of 99%. The black matrix had a surface resistanceof 10⁹ Ω/cm². Thus, it was found that the color filter was producedwithout forming a thin film on the electrodes other than those forpassing electricity. Also, it was found that the color filter waselectrically conductive since the color filter had a resistance of 10⁵Ω/cm².

EXAMPLE 5

The same procedures as used in Example 2 were repeated except that therewas used a resist material for a light-shielding film prepared by mixinga conductive particle dispersed resist (containing chromium oxide asconductive particle); an insulating transparent resist (acryl typeresist ARONIX cellosolve acetate 10% solution; Manufactured by ToaGosei); an insulating organic dye (red) dispersed resist (CR;Manufactured by Fuji Hunt Electronics Technology) and an insulatingorganic dye (blue) dispersed resist (CB; Manufactured by Fuji HuntElectronics Technology) at a weight ratio of 1:1.5:5:5, and that therotation speed for spin coating was changed to 2000 rpm during blackmatrix formation, to produce a color filter.

As a result, the black matrix had a film thickness of 1.9 μm, and alight-shielding ratio of 97%. The black matrix had a surface resistanceof 10¹³ Ω/cm². Thus, it was found that the color filter was producedwithout forming a thin film on the electrodes other than those forpassing electricity. Also, it was found that the color filter waselectrically conductive since the color filter had a resistance of 10⁵Ω/cm².

EXAMPLE 6

The same procedures as used in Example 2 were repeated except that therewas used a resist material for a light-shielding film prepared by mixingan insulating organic dye (red) dispersed resist (CR; Manufactured byFuji Hunt Electronics Technology); an insulating organic dye (blue)dispersed resist (CB; Manufactured by Fuji Hunt Electronics Technology);an insulating organic dye (black) dispersed resist (K0084; containingPerillene Black; Manufactured by BASF); and an insulating transparentresist (acryl type resist ARONIX cellosolve acetate 10% solution;Manufactured by Toa Gosei) at a weight ratio of 15:15:30:40, and thatthe rotation speed for spin coating was changed to 2000 rpm during blackmatrix formation, to produce a color filter.

As a result, the black matrix had a film thickness of 1.9 μm, and alight-shielding ratio of 97%. The black matrix had a surface resistanceof 10¹³ Ω/cm². Thus, it was found that the color filter was producedwithout forming a thin film on the electrodes other than those forpassing electricity. Also, it was found that the color filter waselectrically conductive since the color filter had a resistance of 10⁵Ω/cm².

EXAMPLE 7

The same procedures as used in Example 2 were repeated except that therewas used a resist material for a light-shielding film prepared by mixingan insulating organic dye (K0084; containing Perillene Black;Manufactured by BASF); and an insulating transparent resist (acryl typeresist ARONIX cellosolve acetate 10% solution; Manufactured by ToaGosei) at a weight ratio of 1:1.4, and dispersing the dye in theinsulating transparent resist, and that the rotation speed for spincoating was changed to 2000 rpm during black matrix formation, toproduce a color filter.

As a result, the black matrix had a film thickness of 1.9 μm, and alight-shielding ratio of 99%. The black matrix had a surface resistanceof 10¹³ Ω/cm². Thus, it was found that the color filter was producedwithout forming a thin film on the electrodes other than those forpassing electricity. Also, it was found that the color filter waselectrically conductive since the color filter had a resistance of 105Ω/cm².

EXAMPLE 8

The same procedures as used in Example 2 were repeated except that therewas used a resist material for a light-shielding film prepared by mixingan insulating organic dye (K0084; containing Perillene Black;Manufactured by BASF); and an insulating transparent resist (TorayPHOTONEECE NMP 3% solution; Manufactured by Toray) at a weight ratio of1:1.5, and dispersing the dye in the insulating transparent resist, andthat the rotation speed for spin coating was changed to 2000 rpm duringblack matrix formation, to produce a color filter.

As a result, the black matrix had a film thickness of 1.9 μm, and alight-shielding ratio of 97%. The black matrix had a surface resistanceof 10¹³ Ω/cm². Thus, it was found that the color filter was producedwithout forming a thin film on the electrodes other than those forpassing electricity. Also, it was found that the color filter waselectrically conductive since the color filter had a resistance of 105Ω/cm².

EXAMPLE 9

The same procedures as used in Example 2 were repeated except that therewas used a resist material for a light-shielding film prepared by mixingan insulating organic dye (red) dispersed resist (CR; Manufactured byFuji Hunt Electronics Technology); an insulating organic dye (green)dispersed resist (CG; Manufactured by Fuji Hunt Electronics Technology);and an insulating organic dye (blue) dispersed resist (CB; Manufacturedby Fuji Hunt Electronics Technology) at a weight ratio of 1.5:1:1, andthat the rotation speed for spin coating was changed to 400 rpm duringblack matrix formation, to produce a color filter.

As a result, the black matrix had a film thickness of 2.9 μm, and alight-shielding ratio of 88%. The black matrix had a surface resistanceof 10¹³ Ω/cm². Thus, it was found that the color filter was producedwithout forming a thin film on the electrodes other than those forpassing electricity. Also, it was found that the color filter waselectrically conductive since the color filter had a resistance of 105Ω/cm².

COMPARATIVE EXAMPLE

The same procedures as used in Example 2 were repeated except that aconductive transparent resist (CK; Manufactured by Fuji Hunt ElectronicsTechnology) was used as a resist material for a light-shielding film, toproduce a color filter.

As a result, the black matrix had a film thickness of 2.4 μm, alight-shielding ratio of 99% and a surface resistance of 10⁵ Ω/cm².Thus, a color filter could not be produced since a thin film was formedon the electrodes other than those for passing electricity during theformation of the first coloring matter layer.

INDUSTRIAL APPLICABILITY

As mentioned above, according to the present invention, a color filtercan be readily produced, which enables a transparent electrode forforming a coloring matter film to be used as a transparent electrode fordriving liquid crystals. In other words, since a coloring matter layeris extremely thin and porous, resulting in low potential resistance downeffect of an electrode located under the coloring matter layer, thecolor filter can be used to directly drive liquid crystals. In thepresent invention, it is not necessary to form a transparent electrodeon the most upper layer, resulting in omission of complicatedpositioning with an electrode. Further, the coloring matter layerprepared according to the present invention is superior to that preparedby a conventional method in conductance, heat resistance, chemicalresistance, light resistance and the like. By the use of this coloringmatter layer, the leveling is easy since the film thickness can befreely adjusted by controlling amount of electricity to be passed.

Accordingly, the color filters of the present invention can be used asseveral filters such as a liquid crystal display device, anelectrochromic display device, a plasma display panel, spectrograph, CCPdevice, and a light controller. More specifically, the color filters canbe effectively used in several fields such as a lap-top type personalcomputer, a word processor, a liquid crystal color TV (portable or wallhanging type), an aurora vision, a view finder for a video camera, awatch, a clock, a measurement equipment panel, an inner panel for anautomotive, a liquid crystal color filter, a liquid crystal projector, acolored glass and the like.

Further, the resist for a light-shielding film according to the presentinvention has excellent properties such as a high insulating propertyand high light-shielding property. Accordingly, the use of the resist ofthe present invention gives a light-shielding film havinglight-shielding ratio which is 50% higher than that prepared using aconventional resist comprising three coloring materials (R, G, B), whencomparing resists having the same thickness. Further, the presentinvention makes it possible to produce an RGB color filter by a micellardisruption method. Thus, after color filter is formed, an electrode forforming a color filter can be used as an electrode for driving liquidcrystals. Furthermore, during the color filter preparation, a resist fora light-shielding film never bothers anything, and can divide smallregions with walls of the resist for the light-shielding film. Thus, aproduction of a stable color filter having no exfoliation or spots, canbe achieved.

We claim:
 1. A process for producing a color filter, the color filterincluding an insulating substrate, transparent electrodes for aplurality of colors, a black matrix and a coloring matter layer, thecolor filter further including, near one side of the surface thereof, anelectrode contact zone having an electrode contact window belt for eachgroup of the transparent electrodes corresponding to each kind of color,the process comprising:(a) forming a lamination of an insulatingsubstrate and patterned transparent electrodes laminated thereon for aplurality of colors, said lamination including an electrode contact zonehaving a plurality of units of electrode lines, each unit having anumber of electrode lines equal and corresponding to the number of thecolors; (b) forming a black matrix on said lamination, said black matrixhaving a surface resistance of not less than 10⁷ Ω/cm² ; (c)simultaneously with the step of forming said black matrix, coveringsections of said electrode contact zone with the material of said blackmatrix so that the material of said black matrix covers all electrodelines except a part of each electrode line for each color in each unitof electrode lines; (d) forming an electrically conductive layer in saidelectrode contact zone over said material of said black matrix and overthe electrode lines for each color so that an electrode contact windowbelt unit is formed for each color and all of the electrode lines in oneelectrode contact window belt unit for one color are electricallyconnected with each other but insulated from the electrode lines inother electrode contact window belt units for the other colors, wherebyall of the transparent electrodes for one color are electricallyconnected and the transparent electrodes for different colors areelectrically insulated from each other; and (e) forming a porouscoloring matter layer on said transparent electrodes by a micellardisruption method for one color at a time by selectively using saidtransparent electrodes.
 2. A process according to claim 1, wherein saidblack matrix is formed by a photo-lithography method using a resist fora light-shielding film comprising at least one of an insulating organicdye dispersed resist and an insulating transparent resist, and a highlight-shielding resist.
 3. A process according to claim 1, wherein saidblack matrix is formed by a photo-lithography method using a resist fora light-shielding film comprising at least two kinds of insulatingorganic dye dispersed resists.
 4. A process according to claim 1,wherein said black matrix is formed by a photo-lithography method usinga resist for a light-shielding film which is an insulating transparentresist containing a black organic dye dispersed therein.